Emily ate 3 slices of pie. Stephanie ate 2 slices. If Emily ate $\dfrac{3}{7}$ of the pie, what fraction of the pie is remaining?
If 3 slices represent $\dfrac{3}{7}$ of the pie, there must have been a total of 7 slices. $\text{fraction of pie remaining} = \dfrac{\text{number of slices remaining}}{\text{number of slices total}}$ Together they ate 5 slices, which leaves 2 out of 7 slices remaining. There is $\dfrac{2}{7}$ of the pie remaining.